Dust cap assembly for tumbler locks



Sept. 10, 1968 0. w. GLASS ETAL 3,400,564

DUST CAP ASSEMBLY FOR TUMBLER LOCKS Filed Oct. 18, 1965 United StatesPatent 3,400,564 DUST CAP ASSEMBLY FOR TUMBLER LOCKS Dwight W. Glass andRobert A. Sewell, Rockford, Ill.,

assignors to National Lock Co., Rockford, III., a corporation ofDelaware Filed Oct. 18, 1965, Ser. No. 497,368 3 Claims. (Cl. 70-455)ABSTRACT OF THE DISCLOSURE A dust cap assembly for tumbler locks havinga locking plug rotatable in a cylindrical housing utilizing a movablecam or pair of cams positioned between the face of the lock plug and adust cap or cover fitting over the face of the plug; the dust cap or.the face of the plug having a recess receiving the cam or cam-s. Thedust cap has an opening therein generally aligned with a keyway in thelock plug, and the plug includes circumferentially spaced pockets on therear surface of the front flange receiving lips formed on an annularflange extending rearwardly of the dust cap. A single cam has an openingto be aligned with the keyway, an outwardly projecting arm received inthe opening in the cap to limit movement of the cam, and an integralcurved spring arm cooperating with a projection in the recess for thecam. If a pair of cams are utilized, the cams meet at a central partingline, each having a sloping lead-in surface and a pair of outwardlycurved integral spring arms opposite the lead-in surface and cooperatingwith projections in the cam recess.

The present invention relates to a dust cap for a pin or plate tumblerlock and more particularly to a two-part dust cap assembly which issnapped onto the plug of a tumbler lock and has a yieldably biased camnormally covering the keyway in the plug to prevent the entry of dust orother foreign matter.

Among the objects of the present invention is the provision of a dustcap assembly for a tumbler lock having a movable cam and a cap or cover.The cam includes an opening to be aligned in one position with thekeyway in the plug and an actuating spring means to yieldably urge thecam to a second position covering the keyway. The cap or cover issnapped over or staked onto the outer face of the plug in the tumberlock and is prevented from rotating relative to the plug.

Another object of the present invention is the provision of a dust capassembly having a cap with a cylindrical depending flange whichencompasses the face of the tumbler plug, and the cap has an interiorrecess receiving a cam. The cap also has an angular lead-in or cammingportion serving to direct the key into the keyway and urge the movablecam :to open position. If a single cam is utilized, it includes aprojection adapted to be engaged by the key at the lead-in surface onthe cap and an opening adjacent the projection to be moved intoalignment with the keyway.

A further object of the present invention is the provision of a dust capassembly having a two-part cam received within the cap. The cam isdivided symmetrically into two parts which are mirror images, each parthaving an integral yieldable biasing means. The two parts are divided atthe center over the keyway and separate upon insertion of a key. The twoparts form a central V-shaped incline or groove to guide the key andforce the cams outwardly in opposite directions to allow the key toenter the keyway.

The present invention also comprehends the provision of a dust capassembly where the face of the plug is recessed to receive the cam orcams and the dust cap is being used as an escutcheon or snap-on scalp.Also the ice dust cap, whether recessed or used as an escutcheon,provides a peripheral ridge overlapping the oute face of the cylindricalhousing for the plug to prevent entry of dust between the plug andhousing.

The present invention further comprehends the provision of a dust capassembly where both the cam or cams and the cap are formed from aresilient plastic material. The dust cap formed from a plastic or otherflexible material can be snapped onto the plug and the cam or cam-s havethe yieldable biasing means formed of the same material and integralwith the cam body.

Further objects are to provide a construction of maximum simplicity,efiiciency, economy and ease of assembly and operation, and such furtherobjects, advantages and capabilities as will later more fully appear andare inherently possessed thereby.

In the drawing:

FIGURE 1 is a front elevational view of a cylinder lock having the dustcap assembly of the present invention secured thereto. I

FIG. 2 is a vertical cross sectional'view through the tumbler lock anddust cap assembly taken on the line 2-2 of FIG. 1.

FIG. 3 is a partial horizontal cross sectional view taken on the line 33of FIG. 1.

FIG. 4 is a front elevational view of a tumbler lock having an alternateembodiment of dust cap assembly secured thereto.

FIG. 5 is a partial vertical cross sectional view taken on the line 5-5of FIG. 4.

FIG. 6 is a partial horizontal cross sectional view taken on the line 66of FIG. 4.

FIG. 8 is a partial vertical cross sectional view taken on the line 88of FIG. 7.

FIG. 9 is a partial horizontal cross sectional view taken on the line9-9 of FIG. 7.

Referring more particularly to the disclosure in the drawing wherein isshown illustrative embodiments of the present invention, FIGS. 1 to 3disclose a cylinder tumbler lock 10 having a cylinder or housing ll'witha peripheral flange 12 on the face thereof and having a longitudinalpassage 13 therethrough which is counterbored at 14 in the flange 12.The counterbored passage receives a cylindrical plug 15 having anenlarged face or flange 16 received in the counterbore 14; the plughousing either conventional pin or plate tumblers.

The diameter of the face 16 of the plug is slightly smaller than thediameter of the counterbore 14 and the face is provided with threeequally spaced recesses or pockets 17 formed on the rear edge of theface 16 of the plug. The plug also includes a conventional keyway 18 fora key (not shown) to be inserted and actuate the tumblers so that theplug 15 can be rotated within the .housing 11 to unlock a door or othermember to which the lock 10 is applied.

A dust cap assembly 19 is provided to cover the face 16 of the plug 15and partially overlap the flange 12 of the housing 11. The assembly ispreferably formed of a plastic or other flexible material and includes acap or cover 21 having a rearwardly extending annular flange 22 providedwith three equally spaced lips 23 which are of slightly greaterthickness than the flange. The flexibility of the cap material allowsthe cap to be snapped over the face 16 of the plug 15 with the annularflange 22 entering the annular space around the plug face 16 in thecounterbore 14 and the lips 23 snapping into the corresponding recessesor pockets 17 so that the cap 21 is retained on the plug 15 and does notrotate relative thereto;

The cap 21 is provided with a peripheral ridge 24 which overlaps theinner periphery of the housing 11 at the counterbore 14 to prevent dustfrom entering therein between the cylinder and the plug 15. The cap alsohas a centrally disposed generally rectangular opening 25 which isgenerally aligned with the keyway 18 as will be later seen, and asemi-circular lead-in camming surface 26 at one side of the keyway 18.The cap 21 is further provided with an interior recess 27 havingparallel side walls 28 to allow for movement of a cam 29.

The cam 29 is also preferably molded from a resilient or flexiblematerial having a generally rectangular body and an integral curvedspring arm 31 projecting from one side of the body. The body is formedwith parallel sides complementary to the sides 28 of the recess 27 inthe cap. The cam also has a rectangular opening 32 therethrough and anoutwardly projecting arm 33 which is received in the opening 25 in thecap. The recess 27 also is provided with one or more interiorprojections 34, one of which cooperates with the outer end of theactuating spring 31 to urge the cam 29 to the left as seen in FIG. 1.

The dust cap assembly 19 is shown in its closed position in FIG. 1 withthe cam 29 urged to the left by the spring 31 so that the arm 33 abutsthe edge of the opening 25 at the lead-in surface 26 whereby the opening32 in the cam is covered by the cap, and the cam closes the opening 25in the cap to prevent entry of dust or other foreign matter into thekeyway 18. When a key (not shown) is utilized to actuate the tumblerlock, the end of the key engages the lead-in camming surface 26 and iscammed against the arm 33 of the cam 29 and urges the arm 33 and cam 29away from the lead-in surface 26 so that the opening 32 in the cam isaligned with the keyway 18 and the opening 25 in the cover to allow thekey to enter the keyway 18 to actuate the lock.

When the key is removed, the spring arm 31 cooperating with theprojection 34 urges the cam 29 to the left in FIG. 1 to close theopening 25 in the cover; the arm 33 in the opening 25 limiting movementof cam 29. The opening 25 in the cover 21 is slightly offset to theright of the axis for the plug as seen in FIG. 1 to receive the arm 33on the cam 28 and allow the keyway to be completely uncovered forentrance of a key.

FIGS. 4 to 6 disclosed an alternate embodiment of the dust cap assembly35 utilized with a tumbler lock identical to that shown in FIGS. 1 to 3with like parts identified with corresponding numerals having asuperscript a. The housing 11 contains a plug with an enlarged face 16having pockets 17 and a keyway 18a.

The dust cap assembly includes a cover or cap 36 having an annularrearwardly extending flange 37 with lips 38 received in the pockets 17to snap the assembly 35 onto the plug 15*. The cover has a peripheralridge 39 overlapping the inner periphery of the flange 12 of the housing11 and a substantially centrally positioned generally rectangularopening 41 therethrough aligned with the keyway 18 Also, the cover hasan interior recess 42 having a pair of parallel sides 43 and generallyequally spaced projections 44 therein.

The cam in the recess 42 is divided into a pair of generally symmetricalparts 45, 45', each part having a pair of diverging outwardly curvedspring arms 46, 46, 46', 46' with the outer end of each arm cooperatingwith one of the projections 44 in the recess. Each part also has agenerally rectangular camming or lead-in surface 47, 47' with the twosurfaces converging to a point where they abut to cover the keyway 18and form a generally V- shaped groove.

In utilizing this embodiment, the key is inserted in the opening 41 inthe cover and engages the lead-in surfaces 47, 47' on the cam parts 45,45', urging the cam parts outwardly against the action of the springarms 46, 46, 46', 46' to expose the keyway 18 and allow the entrance ofthe key therein. When the key is removed, the spring 4 arms 46, 46, 46',46' urge the cam parts 45, together to cover the keyway.

FIGS. 7 to 9 disclose a third embodiment of dust cap assembly 48 appliedto a tumbler lock 10 which is generally similar to the embodiment ofFIGS. 1 to 3 except that the dust cap 49 is not provided with aninterior recess for the cam. The cover or cap 49 includes the annularflange 51 with the lips 52 cooperating with the pockets 17 on the plug15 and the opening 53 therein adjacent a lead-in surface 54. The plug 15is rotatable in the housing 11 has a keyway 18 extending therethroughand is provided on the face 16 with a recess 55 having a pair ofgenerally parallel sides 56 and a pair of interior projections 57.

The cam 58 is identical with the cam 29 of FIGS. 1 to 3 and includes thespring arm 59 at one side cooperatcams 45, 45' with each cam having apair of resilient legs 46, 46 or 46', 46', as shown in FIGS. 4 to 6,could be utilized instead of the single cam 58 shown. To utilize thedouble cam arrangement, four projections 57 would be rearm or projection62 at one side of the opening; the arm 62 projecting through the opening53 in the cap 49 for 55 1s provided in the enlarged face 16 of the plug15 it is obvious that the cam assembly having the pair of entiallyequally spaced lips, the enlarged head of said plug being spaced fromthe housing to receive said annular quired in the recess instead of twoand the cap 49 would have the rectangular opening 53 centrallypositioned in alignment with the keyway 18 After assembly of either ofthe three embodiments, the dust cap is held captive against a forcedpop-off since the three lips overlap with the back of the plug flange isgreater than the clearance between the cylinder or shell limitedmovement. Operation of the dust cap assembly 48 is identical with thatof the assembly 19 of FIGS. 1 to 3.

In the embodiment of 'FIGS. 7 to 9 where the recess counterbore and thedust cap diameter. Although the dust cap assembly has been shown aspreferably formed of a plastic or similar resilient material, either thedust cap or the cam or both members could be formed of metal by diecasting, compression of powdered metal, stamping, etc. If the cam memberis formed of metal, a spring would have to be staked in place, and ifthe cap were made of metal, a staking operation would be necessary inthe area of the pockets in the back of the plug head or flange to retainthe cap in place.

Having thus disclosed the invention, we claim:

1. A dust cap assembly for a tubular lock having a rotatable plug withan enlarged head and a keyway therethrough within a lock housing,comprising a dust cap extending across the enlarged head of the plug andpartially overlapping the end of the housing, said dust cap having agenerally, central opening and an annular rearwardly extending flangeterminating in a plurality of circumfering with one of the projections57 on the plug 15 a generally central opening 61 with an outwardlyextending flange and having a plurality of circumferentially equallyspaced pockets in the rear surface thereof to receive said lips, and agenerally flat cam positioned between said dust cap and the enlargedhead of said plug for reciprocation between an open position uncoveringthe keyway and a closed position covering the keyway, said cam having anopening therethrough adapted to be aligned with said key- Way in openposition, an arm formed on said cam adjacent said opening to projectoutwardly through the opening in said dust cap and limit reciprocationof said cam, and an integral resilient arm extending outwardly from saidcam and curving to generally parallel with said first mentioned arm andcooperating with the dust cap to bias said cam to closed position.

2. A dust cap assembly as set forth in claim 1, in which said dust caphas a recess receiving said cam therein, said cam and recess havingcooperating parallel surfaces to guide the reciprocable movement of saidcam, and at least one interior projection in said recess cooperatingwith the end of said resilient arm.

3. A dust cap assembly for a tumbler lock having a rotatable plug withan enlarged head and a keyway therethrough within a lock housing,comprising a dust cap extending across the enlarged head of therotatable plug and partially overlapping the end of the lock housing,said dust cap having a centrally positioned opening therein aligned withthe keyway and an annular rearwardly extending flange terminating in aplurality of circumferentially equally spaced lips, the lock housingbeing spaced from the enlarged head of the plug to provide an annularspace accommodating said annular flange, said enlarged head having aplurality of circumferentially equally spaced pockets in the rearsurface thereof to receive said lips, said dust cap having a recesstherein facing said plug, and a pair of oppositely moving generally fiatcams received in said recess, each cam having a pair of oppositelyoutwardly curved resilient arms integral with said cam and urging thecams together to cover the keyway, a downwardly and inwardly slantingcamming surface on the inner edge of each cam, said slanting surfacescooperating to form a generally V-shaped recess cooperating with a keyto separate the cams and uncover the keyway, said recess and said camshaving complementary parallel guiding surfaces to guide reciprocation ofsaid cams, and an interior projection in said recess cooperating witheach resilient arm to bias the cams to closed position.

References Cited UNITED STATES PATENTS 952,643 3/1910 Roche 70-4551,560,868 11/1925 Shinn 70-455 1,652,897 12/ 1927 Hill 70-455 X1,757,387 5/1930 Rabkin. 1,811,141 6/1931 Leventhal 70-455 1,965,9427/1934 Jacobi 7( )455 2,874,563 2/1959 Schlage 70455 2,956,430 10/1960Simmons 70-455 3,267,707 8/1966 Adams 70-455 X FOREIGN PATENTS 1,368,2536/1964 France.

606,252 7/ 1960 Italy.

606,253 7/ 1960 Italy.

OTHER REFERENCES German printed application, Wolf et 211., 1,118,649,November 1961.

MARVIN A. CHAMPION, Primary Examiner.

P. TEITELBAUM, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,400,564 September 10, 1968 Dwight W. Glass et al.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 4, after line 17, insert ing with one of the projections 57 onthe plug 15 a generally central opening 61 with an outwardly extendingarm or projection 62 at one side of the opening; the arm 62 projectingthrough the opening 53 in the cap 49 for limited movement. Operation ofthe dust cap assembly 48 is identical with that of the assembly 19 ofFIGS. 1 to 3 In the embodiment of FIGS. 7 to 9 where the recess 55 isprovided in the enlarged face 16 of the plug 15 it is obviou that thecam assembly having the pair of lines 21 to 26, cancel "arm orprojection 62 at one side of the opening; the arm 62 projecting throughthe opening 53 in the cap 49 for 55 is provided in the enlarged face 16of the plug 15 it is obvious that the cam assembly having the pair ofentially equally spaced lips, the enlarged head of said plug beingspaced from the housing to receive said annular"; lines 34 to 36, cancel"limited movement. Operation of the dust cap assembly 48 is identicalwith that of the assembly 19 of FIGS. 1 to 3. In the embodiment of FIGS.7 to 9 where the recess"; line 47, "tubular" should read tumbler lines54 and 55, cancel "ing with one of the projections 57 on the plug 15 agenerally central opening 61 with an outwardly extending" and insertentially equally spaced lips, the enlarged head of said plug beingspaced from the housing to receive said annular Signed and sealed this10th day of February 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting OfficerCommissioner of Patents

